1. Field of the Invention
The present invention relates generally to advanced wastewater treatment device having movable dividers and, more particularly, to an advanced wastewater treatment device having movable dividers, which improves a biological treatment process for sewage and wastewater, thus enhancing the treatment efficiency of an A2O (Anaerobic-Anoxic-Oxic) process of an advanced wastewater treatment process and acquiring the stability of the quality of treatment water.
2. Description of the Related Art
A general sewage and wastewater treatment process is a biological process using activated sludge, in which aerobic microorganisms oxidize organic matter of sewage and wastewater under aerobic condition, thus reducing the concentration of organic matter in treatment water. A settling tank is operated to maintain the concentration of microorganisms in a reaction bath, and to prevent the discharge of particles and activated sludge to treatment water.
However, the standard activated sludge process varies in settleability depending on conditions such as the temperature, pH, or the concentration of contaminants in influent water, so that the final quality of the treatment water is greatly changed. If the activated sludge is included in the final treatment water by the deterioration of settleability, the concentration of organic matter becomes undesirably high because of the discharged activated sludge.
Further, the general standard activated sludge process may treat only carbon-based organic matter, but may not treat nitrogen or phosphorus that causes the eutrophication of rivers or lakes. In order to satisfy the effluent standard of wastewater treatment facilities which has been made more strict, a variety of processes have been proposed.
The most general and universal method of treating nitrogen or phosphorus is an A2O process, in which microorganisms undergo multi-stage processes having anaerobic, anoxic, and aerobic conditions, thus treating organic matter and nutrient salts of influent sewage and wastewater. Under anaerobic condition, the microorganisms discharge phosphorus. As the microorganisms grow under aerobic conditions, the luxury uptake of the discharged phosphorus occurs, so that the phosphorus is removed when the sludge is carried out.
Under aerobic condition, as described above, the growth of the microorganisms, the luxury uptake of the phosphorus and the oxidation of the microorganisms occur. Simultaneously, nitrogen is converted from ammonia through nitrite (NO2−) to nitrate (NO3−). The nitrogen converted in this way flows into an anoxic bath through internal return, so that it is changed into nitrogen gas (N2) under anoxic condition and released into the atmosphere.
Most biological processes of removing nitrogen and phosphorus are based on the A2O process. However, the existing A2O process has a drawback in that, if each reaction bath is built at the time of designing the process, a residence time for treatment is fixed regardless of changes in properties of influent water.
The properties and temperature of wastewater vary greatly according to the season. In Korea, for example, where there are four distinct seasons and the amount of water used and water temperature varies according to which time of the year it is, treatment efficiency differs for the same microorganism concentration and residence time.
However, a change in the properties of raw water resulting from seasonal variation maintains a predetermined pattern. Water temperature, for example, as well as the amount of water used, show predictable changes depending on the season. A change in the concentration of raw water thus follows a predetermined pattern.
Therefore, a change in residence time of the biological treatment process depending on a change in properties of raw water may be predicted through a model.